Mercury-vapor lamp.



No. 838,280. PATENTED DEC. 11, 1906. H. V. SUM-JENSEN.

MERCURY VAPOR LAMP.

APPLICATION FILED APB.25. 1905. RENEWED NOV.14, 1906.

UNITED STATES PATENT OFFICE.

Specification of Letters Patent Patented Dec.'11, 1906.

Application filed April 26, 1906. Renewed November 14. 1906. Serial No. 848,437.

To all whom it may concern:

Be it known that I, HANS VroeoSnM-JnN- sEN, physician, a citizen of the Kingdom of Denmark, residing in Copenhagen, Denmark, have invented certain new and useful Improvements in and Relating to Mercury-Va- 1pier I iamps, of which the following is a specication.

The original method of forming an electric arc between two mercury electrodes inclosed in a vacuum has been to produce by a simple mechanical operation-such as tilting, shaking, or the likean evanescent. metallic connection of mercury between the electrodes, through the subsequent interruption of which the arc is formed.

Where a short are is concerned, same may be formed easily and securely in the aforesaid manner; but when it is desired to produce arc of a greater lengthfor instance, one meter or thereabout-the above method is unsatisfactory and cannot be relied upon, as the interruption of the metallic mercury connection established between the electrodes by the mechanical operation takes place too quickly and suddenly and conseqpently the arc formed is gener y extinguis ed. This defect may now be remedied in various ways. Thus an inductive resistance may be inserted in the electric conductor in such a manner that by the sudden interruption of. the are an induced current of a high electromotive force is produced which is suflicient to strike the interrupted arc afresh. Advantage may also be taken of the fact that a prolongation of the negative electrode extending close to the positive may exist during the burning of the mercury lamp without affecting the formation of the are which travels along the said prolon ation of the negative electrode until it reaches that part of same which is farthest from the positive electrode. Consequently it is only necessa to make and again interrupt the connection between the positive electrode and the prolongation of the negative electrode-that is to say, the connection is only interrupted suddenl to strike a short arc-and the are produced t en travels slowly along the prolongation of the negative electrode, which continues .to exist during the burning of the lamp. Both the said methods are already known; but a third method may, however, be adopted by taking care that the metallic mercury connection between the electrodes produced by the mechanical operation is interrupted slowly and that the distance between the electrodes is increased gradually in such a manner as to give the are time to assume its full length between the receding electrodes, and the particular way in which this may be accomplished is the object of the present invention.

In the annexed drawing is shown, by way of example, one embodiment of thepresent invention. v p

a is a lass tube having at each end a receptacle and c, filled with mercury surrounding in the ordinary manner the electrodes (1 and e. The receptacle 0 has fused into it an auxiliary alembic-shaped glass receiver f, the neck 9 of which is open at the top and has a small opening it level with the surface (if the mercury. T e vessel f contains a certain amount of mercury. The striking of the arc is accomplished in the following manner: If we imagine the tube a standing in an inclined position, with the vessel f lowermost, themercury in the vessel f will run out. of same when the tube a is sufiiciently inclined. When next the tube a is turned back to its iormer horizontal position, with the vessel f in he position shown in the drawing, the tube a will contain sufiicient mercury to permit of metallic conducting connection between the electrodes. It will be understood that the mercury flows back to the vessel f ve slowly through the hole h. By means of t is slow return the metallic conducting connection between the mercury electrodes is gradually interrupted, and if the current is flowing an arc will be formed at oiie end of the tube, which will extend very slowly as the mercury recedes. When the mercury has resumed its normal position, the arc will have attained its full length between the electrodes; quently there will be no other conducting matter in the space between the electrodes when the lamp is burnin than mercurial vapors, and when the lamp 1S lighted either electrode may form the anode or the cathode.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a mercury-vapor lamp, a tube having receptacles for mercury electrodes, an auxiliary vessel fused into one of said receptacles, said auxiliary vessel being open at the top and adapted to contain a certain amount? of mercury and having a hole in its neck portion, said hole being situated at the level of the Conse- 5 mercury electrode, substantially as: described I ually Withdrawn from the tube portion and with reference to the accompanying drawings i the arc lengthenedslowly, as and for the purand for the purpose specified. pose set forth.

2. In a mercury-vapor lamp, a tube having i In testimony that I claim the foregoing as receptacles for mercury electrodes, one of said my invention I have signed my name in presl5 electrodes having an auxiliary vessel or chamence of two subscribing witnesses. ber therein from which the mercury is adapt- I HANS VIGGO SIIM-JENSEN; ed to be displacedwhen the tube is tilted, and l Witnesses: means whereby the mercury renters said I CECIL VILHELM SoHoN, 1o vessel or chamber slowly, whereby it is grad- F. A. USSING. 

